A prospective national study of acute renal failure treated with RRT: incidence, aetiology and outcomes.

BACKGROUND: Acute renal failure (ARF) is a diverse condition with no standardized definition and is managed in several sub-specialty areas within hospitals. Its incidence and aetiology are unknown and studies show a wide range of incidences. ARF is becoming more common as the population ages leading to the hypothesis that the incidence is much higher than previous estimates. METHODS: This prospective population study investigated the incidence, aetiology and outcomes of ARF based on a standardized classification of ARF treated by renal replacement therapy (RRT) in all sub-specialty areas within hospitals where such treatment takes place. Data were collected prospectively on all patients starting RRT for ARF within three 12-week periods in 2002. RESULTS: Two hundred eighty-six adults per million population (pmp) per year received RRT for ARF. The incidence increased with age and pre-existing comorbid illness. Two hundred twelve adults pmp per year had no evidence of pre-existing chronic kidney disease (CKD) and the remainder had acute on CKD. The median age was 67 years. Fifty-one percent of the patients received their first RRT treatment in a critical care setting. Sepsis was the most common aetiological insult contributing to ARF in 48% of the patients. Mortality was high with 48% dying within 90 days of starting RRT. Age, comorbidity, sepsis and recent surgery were independent risk factors for death in those with no pre-existing CKD. DISCUSSION: This is the first national study to describe ARF treated with RRT in all hospital locations. The hypothesis that ARF occurs more frequently than previously thought has been confirmed. This study provides data upon which to base effective decision making for prevention, patient care and resource planning for patients with ARF.